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Biomedical subjects

C F Dowd

Publications and source records attributed to C F Dowd.

At least 91 records · Page 5Linked to original sources
PubMed1994

Intracranial aneurysms. Evolution and future role of endovascular techniques.

Treatment of patients with an intracranial aneurysm by interventional neurovascular techniques has made tremendous advances over the past decade. Innovative occlusion devices have included detachable latex and silicone balloons, liquid polymers, intravascular lasers, and stents. As this technology continues to evolve, treatment options will expand and morbidity will continue to decline. The indications for treatment using minimally invasive surgical techniques will alter current management for these difficult and challenging vascular disorders.

Animals↗
PubMed1993

Treatment of giant intradural (perimedullary) arteriovenous fistulas.

Ten patients with giant intradural spinal arteriovenous fistulas (perimedullary Types II and III) were treated with embolization alone (three patients) or in combination with surgery (seven patients). Their ages at the time of treatment ranged from 2 to 40 years, with a mean of 19.5 years. The indications for treatment included progressive myelopathy in five patients, spinal subarachnoid hemorrhage in four, and acute paraplegia in one. Associated conditions included Rendu-Osler-Weber syndrome in two patients, and Cobb's syndrome in two patients. In one patient, the cause of the fistula may have been related to epidural anesthesia traumatizing a low tethered cord. Angiographically, the fistulas were subclassified in three groups: a single-hole fistula supplied by a single feeding medullary artery (three patients); a single-hole fistula supplied by multiple medullary arteries (three patients); and multiple separate fistulas supplied by multiple medullary arteries (four patients). Eight patients were classified as perimedullary Type III and two as perimedullary Type II. Embolic agents were delivered from transarterial routes in 14 procedures and transvenous routes in 2 procedures. A total of 16 embolizations and 8 operations were performed in 10 patients. Seven patients were cured of their fistula (as demonstrated by angiography), two patients had 5% residual filling and are scheduled for future therapy. One refused a follow-up angiographic examination. Complications related to embolization included rupture of the anterior spinal artery by a detachable balloon, resulting in transient worsening of paraplegia with recovery to baseline. Transient worsening of symptoms after surgery was common, but all patients returned to baseline or better. Dramatic improvement was observed in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Transluminal angioplasty for atherosclerotic disease of the vertebral and basilar arteries.

Transluminal angioplasty for hemodynamically significant stenosis (> 70%) involving the posterior cerebral circulation is now being performed by the authors in selected cases. A total of 42 lesions affecting the vertebral or basilar artery have been successfully treated by percutaneous transluminal angioplasty techniques in 41 patients. The lesions involved the proximal vertebral artery in 34 cases, the distal vertebral artery in five, and the basilar artery in three. Patients were examined clinically at 1 to 3 and 6 to 12 months after angioplasty. Three (7.1%) permanent complications occurred, consisting of stroke in two cases and vessel rupture in one. There were four (9.5%) transient complications (< 30 minutes): two cases of vessel spasm and two of cerebral ischemia. Clinical follow-up examination demonstrated improvement of symptoms in 39 cases (92.9%). Radiographic follow-up studies demonstrated three cases (7.1%) of restenosis involving the proximal vertebral artery; two were treated by repeat angioplasty without complication, and the third is being followed clinically while the patient remains asymptomatic. In patients with significant atherosclerotic stenosis involving the vertebral or basilar artery territories, transluminal angioplasty may be of significant benefit in alleviating symptoms and improving blood flow to the posterior cerebral circulation.

Adult↗
PubMed1993

Grading venous restrictive disease in patients with dural arteriovenous fistulas of the transverse/sigmoid sinus.

Dural arteriovenous fistulas of the transverse/sigmoid sinus usually cause pulse-synchronous bruit but may present catastrophically. Current systems for classifying these vascular malformations do not consider obstruction of venous outflow, which increases the risk of intracranial hemorrhage due to retrograde flow via cortical veins. The authors have developed a grading system based on the severity of venous restrictive disease determined by superselective angiography. In a retrospective analysis of 25 patients with dural arteriovenous fistulas of the transverse/sigmoid sinus treated between 1988 and 1990, the grade of venous restrictive disease reflected the clinical presentation. Visual symptoms and central nervous system hemorrhage were more common in patients with cortical venous drainage and more severe distal venous occlusion (Grade 3: 31% and 31%, respectively; Grade 4: 67% and 100%, respectively) than in patients with cortical venous drainage and mild-to-moderate venous restrictive disease (Grade 2: 13% and 0%, respectively) or those without venous outflow (Grade 1: 0% and 0%, respectively). These preliminary results suggest that this grading system may be useful for predicting the risk of catastrophic clinical presentation and for guiding therapeutic decision-making in patients with dural arteriovenous fistulas of the transverse/sigmoid sinus. A prospective study of a larger number of patients is needed to validate the predictive value of this new grading system.

Adult↗
PubMed1993

Endovascular treatment of vertebral artery dissections and pseudoaneurysms.

Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.

Adult↗
PubMed1992

Intravascular balloon dilatation therapy for intracranial arterial vasospasm: patient selection, technique, and clinical results.

Patients presenting with symptomatic intracranial arterial vasospasm are now being treated by interventional neurovascular techniques in selected cases. From a percutaneous transfemoral approach, a custom-designed silicone microballoon can be guided through the intracranial vessels, and inflated to dilate the spastic vessel(s). This technique has been useful for both focal and diffuse areas of spasm. In clinical trials, 28 patients, ranging in age from 15-73 years have been treated. A total of 99 vascular territories have been successfully dilated in both the anterior and posterior circulations. Clinical improvement following treatment was observed in 17 cases (60.7%). Technical complications directly related to therapy included 2 cases (7.1%) of vessel rupture. In long term clinical follow-up 17 patients (60.7%) had good to excellent outcome, 2 patients (7.1%) remained in poor condition, and 9 patients (32.1%) died despite therapy. In patients presenting with symptomatic intracranial arterial vasospasm who are unresponsive to medical therapy, treatment by balloon angioplasty techniques may help to improve cerebral perfusion and clinical outcome of the patient.

Adolescent↗
PubMed1992

Intractable complex partial seizure: correlation of magnetic resonance imaging with pathology and electroencephalography.

We prospectively analyzed MR studies of 32 patients with intractable complex partial seizures, who later underwent resection of EEG-proven seizure foci. Twenty-seven patients were imaged at 1.5, 4 at 0.35, and 1 at 0.5 Tesla. Correlation was obtained on all patients with EEG and surgical pathology. Of 19 patients with mesial temporal sclerosis (MTS), 13 exhibited an MR abnormality at the site of pathology as determined by EEG and surgery. Abnormalities included increased (8) or decreased (1) signal intensity, distortion of gray-white interface (1) and temporal lobe atrophy (3). Six patients had no abnormalities at the site of the diseased focus. MR was more sensitive in patients with other structural lesions which included tumor, encephalitis, polymicrogyria, cryptic vascular malformation, and tuberous sclerosis. Prior studies indicate some usefulness of MR in intractable seizure patients, but many report relative insensitivity of MR in defining an abnormality (as low as 11%). Our results demonstrate the usefulness of high-resolution thin-section multiplanar MR using cardiac gating or flow compensation techniques in this patient population.

Atrophy↗
PubMed1991

Interventional neurovascular treatment of a giant intracranial aneurysm using platinum microcoils.

A 70-year-old woman presented with symptoms of progressive cerebellar dysfunction due to mass effect from a giant, expanding, posterior fossa aneurysm arising from the distal vertebral artery. The aneurysm contained thrombus and had a broad-based neck. From a transfemoral approach, with the patient under local anesthesia, a 2.2 French microcatheter was guided through the vertebral artery and placed directly into the aneurysm. Six 5 x 15-mm platinum microcoils were deposited into the residual lumen of the aneurysm, resulting in complete thrombosis with obliteration of the aneurysm and preservation of the parent artery. Endovascular coil embolization therapy by interventional neurovascular techniques may provide a therapeutic alternative in the management of surgically difficult symptomatic intracranial aneurysms.

Aged↗
PubMed1991

Direct endovascular thrombolytic therapy for dural sinus thrombosis.

Three patients, ages 51 to 71 years, sought treatment for symptomatic dural sinus thrombosis with occlusion and were treated by direct sinus perfusion with urokinase. All three patients had a dural arteriovenous fistula; one involved the inferior petrosal sinus and two involved the transverse sinus. Clinical findings included papilledema, diminished visual acuity, decreased mentation, and cranial nerve palsies. Diagnosis was made by cerebral arteriography and confirmed by sinus venography. All three patients were treated by a transjugular direct infusion of urokinase. In one patient, a transfemoral venous approach used initially was discontinued because of an infection. The period of continuous infusion for thrombolysis ranged between 4 and 10 days. In two patients, the clinical signs and symptoms improved with angiographic evidence of clot lysis and dural sinus recanalization. Angiography indicated that one patient had a partial resolution of a clot in the torcular herophili and transverse sinus but showed no clinical improvement. These preliminary results suggest that transjugular local infusion of thrombolytic agents can be an effective treatment for symptomatic, thrombosed dural sinuses. This selective lysis avoids thrombolytic effects that could aggravate or produce systemic hemorrhagic complications.

Aged↗
PubMed1991

Intracranial aneurysms: interventional neurovascular treatment with detachable balloons--results in 215 cases.

Patients with complex or surgically difficult intracranial aneurysms are being treated with interventional neurovascular techniques. With neuroleptic anesthesia and a transfemoral femoral approach, a silicone micro-balloon can be flow directed through the intracranial circulation, guided directly into the aneurysm, and detached. The aneurysm is thus eliminated from the circulation, and the parent artery is preserved. For broad-based or ectatic aneurysms, test occlusion followed by permanent occlusion of the aneurysm and parent vessel can be performed. Since 1981, 211 patients with 215 aneurysms, including 177 cases involving the anterior and 38 cases involving the posterior circulation, have been treated with this technique. In 127 cases (59.1%), the parent vessel was occluded; in 88 cases (40.9%), primary occlusion of the aneurysm was achieved with preservation of the parent artery. Therapy-related complications included 21 deaths (9.8%) and 16 strokes (7.4%). Follow-up examinations were performed at 1, 3, and 12 months after treatment, and follow-up ranged from 5 months to 9 years. In patients in whom standard surgical therapy fails or for aneurysms in surgically inaccessible anatomic locations, interventional techniques that make use of detachable balloons may be a useful therapeutic alternative.

Adult↗
PubMed1991

A variant of arteriovenous fistulas within the wall of dural sinuses. Results of combined surgical and endovascular therapy.

Dural arteriovenous (AV) fistulas are thought to be acquired lesions that form in an area of thrombosis within a sinus. If the sinus remains completely thrombosed, venous drainage from these lesions occurs through cortical veins, or, if the sinus is open, venous drainage is usually into the involved sinus. Among 105 patients with dural AV fistulas evaluated over the the past 5 years, seven had a unique type of dural AV fistula in the superior sagittal, transverse, or straight sinus in which only cortical venous drainage occurred despite a patent involved sinus; the fistula was located within the wall of a patent dural sinus, but outflow was not into the involved sinus. This variant of dural AV fistulas puts the patient at serious risk for hemorrhage or neurological dysfunction caused by venous hypertension. Three patients presented with hemorrhage, one with progressive neurological dysfunction, one with seizures, and two with bruit and headaches. A combination of surgical and endovascular techniques was used to close the fistula while preserving flow through the sinus.

Adult↗
PubMed1990

Dural arteriovenous fistulas supplied by ethmoidal arteries.

Eight patients with dural arteriovenous fistulas (DAVFs) located on the floor of the anterior cranial fossa and supplied by enlarged ethmoidal branches of the ophthalmic artery are described. Five patients showed the classical symptom of intracerebral hemorrhage (all five had ipsilateral frontal lobe hematomas and one also had an associated a subdural hematoma). Two patients exhibited atypical symptoms of proptosis, chemosis, elevated intraocular pressure, and loss of vision secondary to an ethmoidal DAVF, which drained posteriorly to the cavernous sinus. The eighth patient exhibited proptosis and chemosis secondary to a cavernous sinus DAVF and was incidentally found to have an asymptomatic ethmoidal DAVF. One additional patient had two separate dural fistulas: one located on the cribriform plate and the second located in the posterior fossa. Seven of the eight patients were cured by surgical excision of the fistula site; in the remaining patient spontaneous obliteration followed a surgical procedure for a cavernous DAVF. DAVFs involving the floor of the anterior cranial fossa usually present with hemorrhage, but can present with ocular symptoms or be entirely asymptomatic and are effectively treated by surgical excision of the fistula site.

Aged↗
PubMed1990

Treatment of carotid-cavernous fistulas associated with Ehlers-Danlos syndrome.

Four patients with Ehlers-Danlos syndrome presented spontaneously with symptomatic direct carotid-cavernous fistulas. Two had previously (2 and 15 years, respectively) had contralateral carotid-cavernous fistulas that were treated with carotid occlusion procedures. The patients' ages at presentation ranged from 19 to 49 years, with a mean of 32 years. All four patients underwent attempted embolization procedures. Two patients had transarterial embolization, one with balloons and liquid adhesives, one with platinum coils and a balloon; the carotid artery was preserved in one and sacrificed in one other. In one patient, who underwent direct puncture of the carotid artery, a massive hematoma causing airway compromise required intubation and emergent surgical repair. The fistula spontaneously closed during this event. In the fourth patient, two transvenous embolizations resulted in markedly decreased flow, but diversion of residual flow to cortical veins produced a fatal pontine hemorrhage. The vascular fragility associated with Ehlers-Danlos syndrome can produce spontaneous direct carotid-cavernous fistulas and makes both diagnostic and therapeutic procedures more difficult.

Adult↗
PubMed1990

Endovascular coil embolization of unusual posterior inferior cerebellar artery aneurysms.

Three patients underwent transarterial platinum coil embolization of unusual posterior inferior cerebellar artery aneurysms. In one case, a giant, bilobed, partially thrombosed aneurysm exhibited marked mass effect on the adjacent medulla. In the second case, diffuse severe cerebral vasospasm, 3 days after subarachnoid hemorrhage, rendered transvascular treatment of the aneurysm difficult. Increasing vertigo and nausea caused by mass effect from an aneurysm previously coated with methyl methacrylate warranted treatment in the third case. Indications for transvascular coil treatment included relative surgical inaccessibility to the aneurysm, and, in our case, inability to perform transarterial detachable balloon therapy. The aneurysms were obliterated by endovascular coil embolization in each case. In the patient with vasospasm, aneurysm treatment followed angioplasty of the major affected cerebral vessels, resulting in significant neurological improvement within 24 hours. Two patients were neurologically intact at the time of discharge, and the third displayed persistent cerebellar signs despite a marked decrease in vertigo and nausea. Reports of transvascular coil embolization of intracranial aneurysms are very rare. Our experience with these patients demonstrates that this technique can be successfully utilized in selected cases.

Aged↗
PubMed1990

Cryptic vascular malformations of the spinal cord: diagnosis by magnetic resonance imaging and outcome of surgery.

The cases of seven patients with intramedullary, cryptic vascular malformations of the spinal cord are reported. In all patients, the clinical course was progressive; a Brown-Séquard syndrome was the most common presenting symptom complex. Magnetic resonance (MR) imaging was performed in all patients. The pattern seen most often was a focus of high signal (on both T1- and T2-weighted MR images) surrounded by a larger zone of low signal (best seen on T2-weighted images), and was remarkably similar for all patients. Six patients underwent surgical exploration; removal of the lesions halted the progression of symptoms in five patients, and one patient had worsened sensory function after surgery. Motor function did not decrease postoperatively in any patient. The one patient who refused surgery has continued to decline neurologically. Histopathological examination of surgical specimens showed a cavernous malformation in one patient, a venous malformation in one, venous varices in two, and organizing hematomas in two; these findings are markedly different from those in previously reported cases of cryptic vascular malformations.

Adolescent↗
PubMed1990

Dural arteriovenous fistulas involving the inferior petrosal sinus: angiographic findings in six patients.

We report the angiographic findings from six patients with intracranial dural arteriovenous fistulas of the inferior petrosal sinus and describe the clinical presentation, vascular anatomy, and embolization techniques used in the treatment of this disorder. Dural arteriovenous fistulas at this site are rare; of 105 patients diagnosed with this abnormality, only six had lesions involving the inferior petrosal sinus. The patients included three men and three women, ranging in age from 41 to 75 years. Patients presented with bruit, proptosis, abducens palsy, or loss of vision, and symptoms were present for up to 1 year prior to diagnosis. These presentations were similar to cavernous sinus arteriovenous fistulas. The arterial supply in all cases was from branches of the external carotid artery and in three cases from the meningohypophyseal trunk of the internal carotid artery. Venous drainage in four patients was via the cavernous sinus to the superior ophthalmic vein. The remaining two patients had drainage primarily to the jugular bulb. In four patients treatment was performed by introducing wire coils into the fistula from the transvenous route. This approach could be used even though the inferior petrosal sinus was thrombosed. One patient, treated early in the series, had only transarterial embolization with both liquid adhesives and particulate embolic agents. One patient had an asymptomatic fistula that was not treated. All patients were cured, as evidenced both angiographically and clinically during the follow-up period. Three patients experienced complications from angiography and treatment: two had transverse sinus thrombosis and one had a transient ischemic attack.

Adult↗
PubMed1989

Transluminal angioplasty of intracerebral vessels for cerebral arterial spasm: reversal of neurological deficits after delayed treatment.

We used intracerebral transluminal angioplasty to treat two episodes of symptomatic vasospasm in a patient recovering from an aneurysmal subarachnoid hemorrhage. The procedures were performed after medical therapies, intravascular volume expansion, and induced arterial hypertension failed to alleviate the patient's neurological condition. The first angioplasty, confined to the right middle cerebral and distal internal carotid arteries, took place more than 30 hours after the onset of left hemiplegia. Despite the subsequent discovery of a small parietal lobe infarct, it brought about a marked improvement in left motor function and may have also limited the spread of necrotic damage. The second angioplasty was necessitated when stenotic segments of the basilar and posterior cerebral arteries caused a 24-hour decline in the patient's mental status. Although delayed in relation to the onset of symptoms, it successfully reversed the patient's comatose state. The use of transluminal angioplasty for vasospasm is generally limited to cases where it can be performed shortly after the onset of neurological symptoms; delaying the procedure increases the risk of hemorrhage from reperfused areas of infarction. Our experience with this patient demonstrates that delayed angioplasty can improve vascular flow to ischemic territory, even after infarction, without complications and with resultant improvement in neurological function.

Angioplasty, Balloon↗